Have content/ create and destroy its own threads.

content/browser/browser_process_sub_thread.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "content/browser/browser_process_sub_thread.h"
 
 #include "build/build_config.h"
 #include "content/browser/notification_service_impl.h"
 
 #if defined(OS_WIN)
 #include <Objbase.h>
 #endif
 
 namespace content {
 
 BrowserProcessSubThread::BrowserProcessSubThread(BrowserThread::ID identifier)
     : BrowserThreadImpl(identifier) {}
 
 BrowserProcessSubThread::~BrowserProcessSubThread() {
-  // We cannot rely on our base class to stop the thread since we want our
-  // CleanUp function to run.
   Stop();
 }
 
 void BrowserProcessSubThread::Init() {
 #if defined(OS_WIN)
   // Initializes the COM library on the current thread.
   CoInitialize(NULL);
 #endif
 
   notification_service_ = new NotificationServiceImpl;
+
+  BrowserThreadImpl::Init();
 }
 
 void BrowserProcessSubThread::CleanUp() {
+  BrowserThreadImpl::CleanUp();
+
   delete notification_service_;
   notification_service_ = NULL;
 
 #if defined(OS_WIN)
   // Closes the COM library on the current thread. CoInitialize must
   // be balanced by a corresponding call to CoUninitialize.
   CoUninitialize();
 #endif
 }
 
 }  // namespace content